Field of the Invention
The present invention relates in general to tiered storage systems, and more particularly, to utilization of storage devices in the tiered storage systems.
Description of the Related Art
Enterprise storage systems are used for improving performance and reliability while minimizing capital and operating cost. For this purpose, such systems use a mix of memory devices. For example, high performance hard disk drives (HDDs) and solid-state drives (SSDs) may be included in enterprise storage systems. However, although SSDs offer a high random access capability per gigabyte (GB) ratio, storage systems with only SSDs are still too expensive. On the other hand, the cost-effective performance of storage systems only including HDDs may be improved for most enterprise computing workloads.
To both reduce storage costs to an IT infrastructure and to meet performance requirements, storage tiering has been widely implemented. Storage tiering is a type of storage architecture that assigns different categories of data to different types of storage media. In particular, the data is categorized primarily on performance requirements, frequency of use, and levels of protection needed, and each category of data is stored on a particular type of storage medium. In some storage systems, such as multi-tier storage systems, a mix of storage device types may be included. For instance, the multi-tier storage system may include one storage tier employing SSDs to provide high performance storage and another storage tier including specific types of HDDs at a lower cost than SSD to provide lower performance to meet customer storage requirements. Examples of such tiering systems include commercial SSD-based multi-tier systems, e.g., IBM System Storage™ Easy Tier.